Back plate latch for machine guns



Feb. 15, 1938. '5, GREEN 2,108,060V

BACK PLATE LATCH FOR MACHINE GUNS Filed DeC. 9, .1936

n E( E a E Inventur* Samuel E Erean refeptedreb. is, 193e' UNITED s-TA'yras PATENT. CF1-ICE BACK PLATE LATCH Fon MACHINE GUNS I A Samuel G. Green, Gray, Ga..

Application December-9,1936, serial Np. 114,972

' s Claims.- (orso- 1) (Granted under the per of March s, 1883, as amended April 3o, 192s; 33o o. 6.157);

'I'he invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon. This invention relates to. a back for machine guns.

'I'he purpose of this invention is to provide a back plate for the receiver of a machine gun in which a latch is conveniently mounted in the lower end of the plate and in orderthat the latch may not be accidentally disengaged from the receiver a locking member is mounted onv the back plate and is arranged to normally hold th latch in latching position.

-To these and other ends, theinvention consists in the construction,arrangement and combinaplate latch tion of elements described hereinafter and pointf..

ed out in the claims forming a part of this specication.

lustrated inthe accompanying drawing, wherein: Fig. 1 is a plan view of the breech end of a machine gun.

Fig.- 2 is a view in lrear elevation. Fig. 3 is a sectional view on theline 3-3 of Fig. 2.

Fig. 4 is a sectional view on the line 3-3 of Fig. 3? 7 Fig. 5 isa plan view of the locking member. Fig. 6 is a sectional view-on the line 6 -6 of Fig. 5.

Fig. '7 is a view in rear elevation and partly in section showing the application of the latch to another type of back plate.

r, Fig. 8 is a sectional Fig. 7.

Referring to Figs. 1 to 6 there is shown a ma-.

chine gun ofthe Browning type comprising a receiver formed of side plates 5 and 6, a bottom plate 1 and' a top plate 8. The innerwalls of the side plates 5 andy 6 are formed' adjacent their rear ends with vertically disposed grooves, respectively 9 and I0, for receiving opposite tongues II-'II on a back plate I2 which is assembled-by a downward movement vand supported by the bottom plate 1. The back plate carries a trigger I3 and a buier lI4 which is disposed longitudinally of the gun and serves in a Well known manner to limit recoil movement of the breech bolt (not shown). An upper bar 'I5 and a lower bar I6 on the back plate carry a pair of hand grips member the 'latch cannot be accidentally disvI 1-I1.4

'I'he lower bar I B ismounted in .two laterally spaced sets of vertically spaced ears I8-I8 and secured thereto by bolts or rivets I9. The lower vtached from the gun.

Q A practical embodiment ofthe invention is il' view on the line 8-8 oi l bar isfspaced from the. lower end 'of the back plate -which has 'a centrally positioned slot 20 for receiving and pivotally mounting the foot of a late h 2 I. A nose 22 on the latch is adapted to engage under the rear end of the bottom Aplate and-the latch is normally'held in latching position by a. helical spring 23 which is seatedin a recess in the under side of the bar I 6 and in a well 24 formed in the body of the'latch. A toe 25 on the foot of the latch is adapted to engage the `back plate and limit movement of the latch under influence of the spring when the back plate` is out of i ts ;na1 assembled'position or is de- The latch is held in engagement with the' bottom plate of the receiver by means of a locking member 26 which is arranged to move in a plane transversely of the plane of movement of the latch.. Thev locking member is channeled to ,em` brace the bar I6 and it is mounted at its right end on a .pivot pin 21 passing through vthe bai I6. A spring 28 bearing on the bar and anchored in the locking member normally holds said memb'er against the bar in which position its lower'. side engages the shoulder 29 of the latch. 'I'he lowerside of the locking member is formed with In operation the locking member must irst be. moved out of engagement with the latch before the latch can be movedout of engagement with the bottom plate. As clearly shown in Fig. 2 both the latch and locking member may be conveniently grasped by the thumb and forenger.

. In the modification shown in Figs. 'l' and 8 the back plate 3| is of a type particularly designed for a. iixed gun and is not provided with a trigger and handle grips while 'the buier 32 is arranged vertically in the back plate. 'Ihe latch 33 is substantially identical with the latch 2I and is arranged in a similar manner. lvA locking member 34, vertically disposed in a slot 35 in the backv plate, is pivotally mounted` to move transversely of the back plate and in a plane transversely oi' the plane of .movement of the latch. A toe 36 on the lower end of the locking member is normally in engagement with the latch 33 to hold "engaged as might occur when the breech end of the gun-is depressed and an obstruction such as the knee of the gunner is struck b y the latch,

' movement, a bar onf the lower part of the back plate, a latch pivottally carried by the back plate underneath the bar and arranged to engage the receiver to hold the back plate in place, a spring.

between the bar and latch, a channeled locking 'member pivotallyf mounted on the b'ar and movable in a plane transversely of the plane of movement of the latch,'and a spring normally holding the locking membler in embracing relation with the bar and in engagement with the latch.

2. In a machine gun, a receiver, a back plate slidably mounted yin the receiver bya lowering movement, a bar on the lower part of the back plate, a latch pivotally carried by the back plate -underneath the bar and arranged to engage the i receiver to hold theback plate in place, a spring between the bar and latch, a locking member pivotally mounted on the bar and movable in a plane transversely of the piane of movement of the latch, and a. spring normally holding the locking member in engagement with the latch.

3. In a machine gun, ia receiver,` a back-I plate slidably mounted in the receiver by a lowering movement, a latch carried in the lower part of the back plate and arranged to engage the receiver to hold the back plate in place, and a locking member carried by the back plate and movable in a .plane transversely of the plane of movement of the latch to engage the latch, said latch and locking member mounted for movement towards each other on being disengaged.

SAMUEL G. GREEN. 

